SELECT 
  a.category_id 
FROM 
  cscart_categories as a 
  LEFT JOIN cscart_categories as b ON b.category_id IN (4564) 
WHERE 
  a.id_path LIKE CONCAT(b.id_path, '/%')

Query time 0.00298

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "1494.60"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "b",
          "access_type": "const",
          "possible_keys": [
            "PRIMARY",
            "p_category_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "category_id"
          ],
          "key_length": "3",
          "ref": [
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.00",
            "eval_cost": "0.20",
            "prefix_cost": "0.00",
            "data_read_per_join": "5K"
          },
          "used_columns": [
            "category_id",
            "id_path"
          ]
        }
      },
      {
        "table": {
          "table_name": "a",
          "access_type": "index",
          "key": "id_path",
          "used_key_parts": [
            "id_path"
          ],
          "key_length": "767",
          "rows_examined_per_scan": 6988,
          "rows_produced_per_join": 776,
          "filtered": "11.11",
          "using_index": true,
          "cost_info": {
            "read_cost": "97.00",
            "eval_cost": "155.27",
            "prefix_cost": "1494.60",
            "data_read_per_join": "4M"
          },
          "used_columns": [
            "category_id",
            "id_path"
          ],
          "attached_condition": "(`webmarco`.`a`.`id_path` like <cache>(concat('4271/4321/4564','/%')))"
        }
      }
    ]
  }
}

Result

category_id
4575
4589
4602
4615
9647
9954
4626
4635
4646
4660
4681
4701
4793
5054
9655
9656
5117
5161
8853
8854
8855
9672
9673
9674
9677
9678
9679
9675
9676
8856
8857
9657
9659
9662
8859